Sight apparatus for use with firearms

ABSTRACT

Sight apparatus for use with firearms are described herein. An example sight apparatus described herein includes a first swivel element removably coupled to a second swivel element. The first swivel element includes a first aperture coaxially aligned with a second aperture of the second swivel element to define a passageway. A coupling element is removably disposed within the passageway to pivotally couple the first swivel element relative to the second swivel element. A retainer is operatively coupled to the coupling element to engage at least one of the first or second swivel portions to prevent movement of the coupling element along a transverse axis of the passageway.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent is a continuation-in-part of International Patent Application Serial No. PCT/EP2007/006782, filed Jul. 31, 2007, which claims priority to German Patent Application 10 2006 011 918.3, filed on Aug. 3, 2006, which are hereby incorporated herein by reference in their entireties.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to sight apparatus and, more particularly, to sight apparatus for use with firearms.

BACKGROUND

Generally, firearms or weapons (e.g., assault rifles, pistols, M-16 machine guns, etc.) often employ sight apparatus or devices to aid an operator (e.g., a shooter) to aim the firearm at an intended or desired target. Some known firearms (e.g., assault rifles) employ a rear sight coupled to a receiver portion of the firearm and a front or fore sight coupled to a muzzle end of a barrel. The front and rear sights must be aligned with the line of sight of the operator or shooter so that the sight apparatus provides horizontal and/or vertical reference points to enable the operator to accurately aim the firearm at a desired target. The front and/or rear sights come in a variety of different configurations such as, for example, a ring sight, a blade sight, an open sight, an aperture sight, etc.

For example, one known example sighting apparatus includes locking pins to form a hinge between a fore sight element and a base element so that the fore sight element may rotate or pivot about the hinge to fold between a stored position and an operating position. In such a configuration, the locking pins are often non-removable and permanently couple to the hinge. Such example sight apparatus having pivotal elements are described in U.S. Patent Publication No. US2005/0188602 and U.S. Pat. No. 6,779,290. In yet another example, a rear sight apparatus includes a rear sight element pivotally coupled to a base element via a pin. Such example of rear sight apparatus are described in German Patent DE 178214 and U.S. Pat. No. 3,675,534.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example sight apparatus described herein.

FIG. 2 illustrates a cross-sectional view of the example sight apparatus of FIG. 1 viewed along line A-A of FIG. 1.

FIG. 3 illustrates another example sight apparatus described herein.

FIG. 4 illustrates an example coupling element to implement the example sight apparatus of FIG. 3.

FIG. 5 illustrates an example swivel element of the example sight apparatus of FIG. 3.

FIG. 6 illustrates the example sight apparatus of FIG. 3 shown in an operating position.

FIG. 7 illustrates the example sight apparatus of FIGS. 3 and 5 shown in a stored position.

FIG. 8 is a partial cross-sectional side view of the example sight apparatus of FIGS. 3, 6 and 7.

DETAILED DESCRIPTION

Certain examples are shown in the above-identified figures and described in detail below. In describing these examples, like or identical reference numbers are used to identify common or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic for clarity. Additionally, several examples have been described throughout this specification. Any features from any example may be included with, a replacement for, or otherwise combined with other features from other examples. Further, throughout this description, position designations such as “above,” “below,” “top,” “forward,” “rear,” “left,” “right,” etc. are referenced to a firearm held in a normal firing position (i.e., wherein the “shooting direction” is pointed away from the marksman in a generally horizontal direction) and from the point of view of the marksman. Furthermore, the normal firing position of the firearm is always assumed, i.e., the position in which the barrel runs along a horizontal axis.

Some known sight apparatus often include a coupling element (e.g., a hinge pin) to pivotally couple a first swivel element (e.g., a blade fore sight) relative to a second swivel element (e.g., a base). In this manner, the first swivel element may pivot or rotate relative to the second swivel element between a stored or stowed position and an operating position (e.g., to aim the firearm at an intended target).

Such known sight apparatus typically include pivotal hinges (e.g., pins) that are non-removable and, thus, permanently couple the first swivel element and the second swivel element. In other words, for example, a pin may be used to permanently couple the first swivel element and the second swivel element and may not be removed from a hinge to disassemble the first swivel element and the second swivel element. Permanently attaching or fixing the first swivel element and the second swivel element is disadvantageous because the first swivel element and/or the second swivel may not be easily removed (i.e., may not be removed without damaging the first swivel element and/or the second swivel element). For example, the first swivel element may become damaged and may need to be replaced.

Additionally or alternatively, with some example firearms such as assault rifles and machine guns, it may be desirable to interchange a first swivel element such as, for example, a blade fore sight with a different swivel element such as, for example, a ring sight. Additionally, in some known examples, a sighting apparatus is often removed or detached from the firearm to utilize a different sighting apparatus such as, for example, optics scope (e.g., a telescopic scope).

The example sight apparatus described herein may be removably coupled to a firearm such as, for example, an assault rifle (e.g., an M-16). More specifically, the example sight apparatus may be disassembled (e.g., without tools) under operating conditions to interchange sight elements, replace damaged components (e.g., sight element), use optic scopes, etc.

An example sight apparatus described herein includes a first swivel element (e.g., a fore sight) pivotally coupled relative to a second swivel element (e.g., a base). Additionally, the first swivel element is also removably coupled to the second swivel element via a coupling element. Thus, the first swivel element may be removed, detached, or decoupled from the second swivel element without causing damage to the firearm, the first swivel element, and/or the second swivel element. In this manner, for example, the first swivel element (e.g., a blade fore sight) may be interchanged with a second swivel element (e.g., a ring sight) that is different from the first swivel element. Additionally, the coupling element and the swivel elements are configured to prevent unintentional or inadvertent removal of the coupling element from the sight apparatus (e.g., due to vibration of the firearm).

Furthermore, the first swivel element may be replaced if it becomes damaged (e.g., during operation) without having to remove the sight apparatus (e.g., the second swivel element) from the firearm. For example, the first swivel element may be detached or removed from the second swivel element of the firearm during operation of the firearm. In other words, the first swivel element may be removed from the second swivel element without having to disassemble a barrel of the firearm and/or remove the second swivel element. Additionally or alternatively, in some examples, the first swivel element may be detached or removed from the second element without the use of, for example, tools.

FIG. 1 illustrates an example sight apparatus 100 that may be used with a firearm (not shown) such as, for example, an assault rifle (e.g., an M16 rifle, etc.), a semi-automatic firearm, an automatic firearm, etc. The example sight apparatus 100 includes a first swivel element or fore sight 1. The fore sight 1 is pivotally coupled to a base or retainer plate 2. In this example, the base 2 includes a receiving portion 3 having an aperture to receive, for example, a muzzle end (not shown) of a barrel of a firearm. For example, the receiving portion 3 receives or couples to a barrel of a firearm via press fit and a form-fit retainer. The base 2 may also include a gas cylinder portion 4. The gas cylinder portion 4 includes a longitudinal recessed-bore (not shown) adapted to receive a piston (not shown) and/or an operating rod (not shown) of the firearm. The receiving portion 3 includes bores (not shown) to fluidly couple a pressurized gas from the barrel of the firearm that is generated when the firearm is discharged or fired. The pressurized gas, in turn, drives the piston and the operating rod, which activates or operates a breech (not shown) of the firearm.

The example fore sight 1 includes a body having a fork-shaped end and a bore that define a first hinge plate 5 and a second hinge plate 5′. The hinge plates 5, 5′ form a recess to receive a hinge link 6 protruding from the gas cylinder portion 4 of the base 2. In other examples, the hinge link 6 may be integrally formed with a barrel of a firearm, a housing of a firearm, a retainer plate, the base 2, etc. The hinge plate 5 includes an aperture or opening 22 and the hinge plate 5′ includes an aperture or opening 16 that coaxially align with an aperture or opening 6′ (FIG. 2) of the hinge link 6. The openings 22, 16 of the respective hinge plates 5, 5′ and the opening 6′ of the hinge link 6 form a passageway 21 that receives a coupling element or hinge pin 7. The coupling element 7 is adapted or configured to pivotally and removably couple the fore sight 1 and the base 2.

FIG. 2 illustrates a cross-sectional view of the example sight apparatus 100 of FIG. 1 viewed along line A-A of FIG. 1. FIG. 2 illustrates the coupling element 7 disposed within the passageway 21 to pivotally couple to the fore sight 1 and the base 2. The coupling element 7 includes a body having a head portion 8 and a retainer or spring clamp 9 at a second end 20 opposite the head portion 8. The coupling element 7 includes an annular groove or recess 10 to retain the spring clamp 9 adjacent the second end 20 of the coupling element 7. The spring clamp 9 and the annular groove 10 are configured (e.g., sized, shaped, etc.) in a manner to enable the spring clamp 9 to radially compress within the annular groove 10 (e.g., so that the spring clamp 9 compress or remains within the shape or contour of the annular groove 10).

As shown in FIGS. 1 and 2, the fore sight 1 includes a bushing 11 coupled to the second hinge plate 5′ to receive the second end 20 of the coupling element 7. In this example, the bushing 11 is integrally formed with the fore sight 1. However, in other examples, the bushing element 11 may be a separate piece that may be welded to the fore sight 1, and/or may be coupled (e.g., via screws) to the fore sight element 1 via any suitable manufacturing process(es).

The bushing 11 includes a bore or opening 17 that defines a portion of the passageway 21. The opening 17 of the bushing 11 is sized larger than the opening 16 of the second hinge plate 5′ to form a shoulder 12. In this manner, the spring clamp 9 extends to engage the shoulder 12 when the coupling element 7 couples the fore sight 1 to the base 2. As a result, the spring clamp 9 engages the shoulder 12 to restrict or prevent movement of the coupling element 7 in an axial direction (e.g., a horizontal direction in the orientation of FIG. 2) of the coupling element 7 within the passageway 21. In this example, the spring clamp 9 at least partially extends behind the shoulder 12 to prevent axial movement of the coupling element 7 when the coupling element 7 is disposed within the passageway 21 as shown in FIG. 2. Additionally, to stop or limit axial movement of the coupling element 7 within the passageway 21 in a direction toward the second hinge plate 5′, the head portion 8 of the coupling element 7 engages the hinge link 6. Thus, in this example, the opening 22 of the hinge plate 5 is larger than the opening 16 of the hinge plate 5′ to accommodate or receive the head portion 8 of the coupling portion 7, and larger than the opening 6′ of the hinge link 6 so that the head portion 8 engages the hinge link 6 when the disposed within the passageway 21 as shown in FIG. 2.

Furthermore, to further limit lateral movement (e.g., horizontal or vertical movement in the orientation of FIG. 2) of the coupling element 7 within the passageway 21, the coupling element 7 is sized substantially similar to the corresponding or respective openings 22, 16 of the hinge plates 5, 5′ and the opening 6′ of the hinge link 6 so that the coupling element 7 may be press-fit within the passageway having a tight tolerance to provide structural support. For example, the opening 22 matably receives the head portion 8 and the openings 6′ and 16 matably receive a stem portion 7′ of the coupling element 7. As a result, the lateral position of the fore sight 1 remains substantially fixed relative to the hinge link 6 as the fore sight 1 pivots relative to the base 2 between the operating position and the stored position without having to re-align or readjust (e.g., re-calibrate) the position of the fore sight 1 relative to a rear sight and/or the base 2.

In this example, to couple the fore sight 1 to the base 2, the coupling element 7 is inserted or disposed within the passageway 21 such that the second end 20 of the coupling element 7 travels from the first hinge plate 5 to the second hinge plate 5′. To facilitate coupling or insertion of the coupling element 7 within the passageway 21, the hinge link 6 may include a bevel or chamfer edge 13. The bevel or chamfered edge 13 compresses or directs the spring clamp 9 within the annular groove 10 of the coupling element 7 when the coupling element 7 is disposed or inserted within the opening 6′ of the hinge link 6. As described in greater detail below, in this example, an opening or gap 14 is formed between the hinge link 6 and the second hinge plate 5′ to enable the spring clamp 9 to expand therein. Thus, a chamfer 15 adjacent the opening 16 (e.g., a restricted opening) of the hinge plate 5′ causes the spring clamp 9 to compress within the annular groove 10 of the coupling element 7 as the spring clamp 9 moves from the gap 14 through the opening 16 in a direction toward the bushing 11.

The second end 20 of the coupling element 7 slides through or within the bushing 11 until the spring clamp 9 moves adjacent the shoulder 12 (e.g., to the right of the shoulder 12 in the orientation of FIG. 2) of the hinge plate 5′ (and the head portion 8 engages the hinge link 6). Because the aperture 17 of the bushing 11 is larger (e.g., slightly larger) than the opening 16 of the hinge plate 5′, the spring clamp 9 expands when the spring clamp 9 is located adjacent the shoulder 12 (e.g., an outer surface of the second hinge plate 5′). When the coupling element 7 is in the position illustrated by FIG. 2 (e.g., a mounting position), the spring clamp 9 partially expands or expands from the annular groove 10 to engage the inner surface of the bushing 11. As a result, the spring clamp 9 also engages the shoulder 12 and/or the outer surface of the hinge plate 5′. In this manner, the spring clamp 9 retains or prevents the coupling element 7 from moving in an axial direction toward the hinge plate 5. Thus, the retainer (e.g., the spring clamp 9) engages at least one of the fore sight 1 or the base 2 (e.g., the hinge link 6) to prevent movement of the coupling element 7 along a transverse axis of the passageway 21.

To decouple or remove the coupling element 7 from the passageway 21, a force is exerted to the second end 20 of the coupling element 7 (e.g., via a tool apparatus, an operator's finger, a cartridge, etc.) in a direction toward the head portion 8 of the coupling element 7. As the force is being applied, the shoulder 12 causes the spring clamp 9 to compress within the annular groove 10 as the coupling element 7 moves through the opening 16 in a direction toward the first hinge plate 5. Because the spring clamp 9 is partially retained in the annular groove 10 when in the expanded position shown in FIG. 2, the spring clamp 9 is retained within the annular groove 10 (i.e., the spring clamp 9 does not slide off of the coupling element 7) as the coupling element 7 is removed from the aperture 17 of the bushing 11 and through the opening 16 of the hinge plate 5′.

Prior to passing through to the opening 6′ of the hinge link 6, the spring clamp 9 expands within the gap 14 between the hinge plate 5′ and the hinge link 6. At this position, the gap 14 receives the spring clamp 9 to prevent axial movement of the coupling element 7 in a direction toward the hinge plate 5. At this position, an external force (e.g., provided via a tool, or by hand) is required to move the coupling element 7 in a direction toward the hinge plate 5.

The gap 14 between the hinge plate 5′ and the hinge link 6 provides an intermediate or safety position when the coupling element 7 is being removed from the sight apparatus 100. In other words, the safety position prevents the coupling element 7 from being removed from the passageway 21 with a single force or motion. In this manner, for example, an operator may be required to apply a second or additional force to the second end 20 (or the head portion 8) of the coupling element 7 to remove the coupling element 7 from passageway 21. Such configuration prevents inadvertent removal of the coupling element 7 from the sight apparatus 100, thereby preventing the fore sight 1 from inadvertently releasing from the base 2. Thus, the spring clamp 9, when expanded to engage the gap 14, provides a safety to prevent inadvertent removal of the fore sight 1 from the base 2.

The hinge link 6 also includes a chamfered edge 13′ opposite the chamfered edge 13 (e.g., facing toward the hinge plate 5′ in the orientation of FIG. 2). The chamfered edge 13′ is configured to compress the spring clamp 9 as the second end 20 of the coupling element 7 passes through hinge link 6, and removed from the first hinge plate 5.

In this example, the geometrical shapes of the annular groove 10, the shoulder 12, the chamfers 13, 13′, 15, and the spring clamp 9 are configured such that the coupling element 7 may be coupled to, and/or removed from, the sight apparatus 100 without the use of, for example, tools. However, in other examples, a tool, a cartridge, etc., may be used to facilitate removal and/or insertion of the coupling element 7 to the sight apparatus 100.

In yet other examples, a tool may be used to remove the coupling element 7 from the sight apparatus 100. For example, a tool may comprise a threaded screw to engage a threaded aperture (not shown) of the bushing 11. In this manner, the tool can facilitate removal of the coupling element 7 coupled with the sight apparatus 100 having a tight fit and/or may prevent damage to the fore sight 1 and/or the base 2 when the coupling element 7 is removed from the passageway 21.

In yet other examples, the example sight apparatus 100 may include a locking mechanism to lock the position of the fore sight 1 when the fore sight 1 is in the operating position and/or the stored position. An example locking mechanism is explained in further detail below in connection with FIG. 3.

FIG. 3 illustrates another example sight apparatus 200. The example sight apparatus 200 includes a first swivel element or fore sight 201 pivotally coupled relative to a second swivel element or base 202 (e.g., a retainer plate) via a hinge pin or coupling element 207. The coupling element 207 removably couples the fore sight 201 relative to the base 202 so that the fore sight 201 may be replaced or interchanged with a different fore sight.

Referring also to FIG. 4, the coupling element 207 has a body that includes a retainer portion. In this example, the retainer portion is integrally formed with the coupling element 207. However, in other examples, the retainer portion may be an insert that slidably engages a stem of the coupling element 207. The retainer portion comprises a contour or keyed portion 209 that defines a first cross-sectional shape of the coupling element 207. Additionally, the retainer includes a radially protruding member or lip 210 eccentrically located relative to the keyed portion 209 to define a second cross-sectional shape of the coupling element 207 different from the first cross-sectional shape. In this example, the first cross-sectional shape (e.g., the keyed end 209) has an arcuate portion and a planar portion. Furthermore, in this example, the second cross-sectional shape includes an arcuate portion and a planar portion, however, the planar portion is further defined by the protruding lip 210.

As shown in FIG. 3, the fore sight 201 is at an intermediate position relative to the base 202. As explained in greater detail below, such intermediate position enables removal and insertion of the coupling element 207 from the sight apparatus 200. The example fore sight 201 includes a first side or hinge plate 205 and a second side or hinge plate 205′. An aperture or opening 216′ of the hinge plate 205 includes a contour or keyed portion or pathway 216. The keyed portion 216 has a cross-sectional shape that corresponds to the second cross-sectional shape of the coupling element 207 (e.g., the cross-sectional shape corresponding to, or formed, by the keyed portion 209 and the protruding lip 210 of the coupling element 207) to enable the coupling element 207 to pass therethrough when the fore sight 201 is in the intermediate position shown in FIG. 3. For example, the keyed portion 216 comprises a cross-sectional shape having an arcuate portion and a planar portion to receive the arcuate portion and the planar portion of the keyed portions 209 and 210 (i.e., the second cross-sectional shape of the coupling element 207).

FIG. 5 illustrates the base 202 of the sight apparatus 200. The base 202 includes hinge link 206 that is to be at least partially disposed between the hinge plates 205 and 205′. The hinge link 206 includes an opening 206′ that coaxially aligns with the opening 216′ of the hinge plate 205 and an aperture (not shown) of the hinge plate 205′ when the fore sight 201 is coupled to the base 202. Additionally, the opening 206′ of the hinge link 206 is configured or shaped to include a counter or keyed portion or pathway 215 corresponding to the keyed portion 209. In other words, the opening 206′ has a cross-sectional shape that corresponds (to receive) the first cross-sectional shape of the coupling element 207. Thus, in this example, the keyed portion 215 has a cross-sectional shape having an arcuate portion and a planar portion corresponding to the arcuate portion and the planar portion of the keyed portion 209 (i.e., the first cross-sectional shape of the coupling element 207).

When the fore sight 201 is tilted or pivoted to the intermediate position as shown in FIG. 3, the keyed portion 216 of the hinge plate 205′ aligns or is substantially parallel to the keyed portion 215 of the hinge link 206. When aligned, the keyed portions 215 and 216 (and the apertures 216′ and 206′) form a passageway 221 that enables the coupling element 207 to slide within the passageway 221 between the hinge plates 205 and 205′. The coupling element 207 can be inserted within (or retracted from) the passageway 221 when the fore sight 201 is at the intermediate position (i.e., when the keyed portions 216, 215, are aligned) relative to the base 202. When coupled to the sight apparatus 200, an end 220 (FIG. 4) of the coupling element 207 is disposed within the opening (not shown) of the hinge plate 205′. In this example, the end 220 of the coupling element 207 has a cylindrical-shaped cross-section.

Thus, the coupling element 207 may be inserted or removed from the passageway 221 when the keyed portions 216, 215, 209, and 210 are coordinated or aligned such that their cross-sectional shapes form a pathway corresponding to the cross-sectional shape of the keyed portion 209 and the lip 210 of the coupling element 207. In this example, such position is in the intermediate position shown in FIG. 3. Such configuration provides a safety that prevents inadvertent removal of the coupling element 207 and, thus, inadvertent removal of the fore sight 201 from the base 202.

FIG. 6 illustrates the example sight apparatus 200 of FIG. 3 shown in an operational position. FIG. 7 illustrates the example sight apparatus 200 of FIG. 3 shown in a stored position. As the fore sight portion 201 swivels or pivots relative to the vent housing 202 between the operating position shown in FIG. 6 and the stored position shown in FIG. 7, the keyed portion 216 deviates or move from the position shown in FIG. 3 (e.g., the keyed portions 216, 215, and/or 209 are not aligned), thereby preventing the coupling element 207 from inadvertently decoupling from the sight apparatus 200. In particular, the keyed portion 216 moves or deviates relative to the keyed portion 215 of the hinge link 206, thereby preventing the protruding lip 210 from axially moving toward the hinge plate 205.

More specifically, the keyed portion 216 deviates from the protruding lip 210, thereby locking, preventing, or blocking the protruding lip 210. In other words, the keyed portion 216 blocks or impedes axial movement of the protruding lip 210 which, in turn, impedes or blocks the axial movement of the coupling element 207 through the passageway 221 when the keyed portion 216 is not aligned with the keyed portion 215. As a result, the keyed portion 216 prevents lateral movement of the lip portion 210 to prevent the coupling element 207 from being extracted or dislodged from the passageway 221 and, thus, the sight apparatus 200. As a result, when the fore sight 201 moves between the operating position (FIG. 6) and the stored position (FIG. 7), the coupling element 207 remains axially fixed along the passageway and is prevented from being removed from the passageway 221. Thus, the keyed portion 209 and the protruding lip 210 engages at least one of the fore sight 201 or the base 202 (e.g., the hinge link 206) to prevent movement of the coupling element 207 along a transverse axis of the passageway 221.

Additionally, the keyed portion 209 matably engages the keyed portion 215 to provide structural support to the hinge assembly. As a result, the lateral position of the fore sight 201 remains substantially fixed relative to the hinge link 206 as the fore sight 201 pivots relative to the base 201 between the operating position and the stored position without having to re-align or readjust (e.g., re-calibrate) the position of the fore sight 201 relative to a rear sight and/or the base 202.

FIG. 8 is a partial cross-sectional side view of the example sight apparatus 200 of FIG. 6. The fore sight 1 may be pivotally fixed or locked relative to the base 202 at the operating position as shown in FIGS. 6 and 8, or at the stored position as shown in FIG. 7. In other examples, the fore sight 201 may be locked at the intermediate position shown in FIG. 3 to facilitate coupling and removal of the coupling element 207, or any other position. The example sight apparatus 200 includes a locking member or body 217 to lock the fore sight 201 in the operating position or the stored position. In this example, a biasing element 217 b biases the locking member 217 toward a locking aperture or detent 218 when the fore sight 201 is at the operating position or a locking aperture or detent 219 when the fore sight 201 is at the stored position. The locking member 217 includes a lever 217 a that protrudes from a slot or opening of the fore sight 201. To disengage the locking member 217 from the detent 218 or the detent 219 to enable pivotal rotation of the fore sight 201 relative to the base 202, an operator moves or displaces the lever 217 a to compress the biasing element 217 b (e.g., in an upward direction in the orientation of FIG. 8). As noted above, the locking mechanism may be implemented with the example sight apparatus 100 of FIGS. 1 and 2.

Thus, when the fore sight 201 is locked in the operating position (e.g., the locking member 217 engages the detent 218) or the fore sight 201 is locked in the stored position (e.g., the locking member 217 engages the detent 219), an operator must disengage the locking member 217 from the detent 218 or 219 to enable pivotal rotation of the fore sight 201 relative to the base 202.

To remove the fore sight 201 from the base 202, the fore sight 201 is positioned to the intermediate position shown in FIG. 3. As noted above, at the intermediate position, the keyed portions 216 and 215 align so that the keyed portion 209 and the protruding lip 210 can slide relative to the keyed portions 216 and 215 to enable the coupling element 207 to axially slide or be removed from the passageway 221.

In another example, to further prevent inadvertent removal of the coupling elements 7 or 207 from the respective sight apparatus 100 or 200, the spring clamp 9 and the annular groove 10 of the coupling element 7 of FIGS. 1 and 2 may be combined or implemented the keyed portion 209 and the protruding lip 210 of FIG. 4. Additionally, the shoulder 12, the gap 14, and the bushing 11 of the fore sight 1 and the chamfer edges 13, 13′ of the hinge link 6 of FIGS. 1 and 2 may be combined or implemented with the keyed portion 216, 215, the detents 218 and 219 of FIGS. 3-8, and/or any combination thereof.

In yet other examples, the hinge link 6 of FIGS. 1 and 2 and/or the hinge link 206 of FIGS. 3-8 may be implemented or configured to be coupled to, for example, a barrel of a firearm, a rail of a firearm, a housing of a firearm, or any other suitable portions of a firearm. In other words, for example, the hinge links 6 and/or 206 may be implemented with a firearm without a receiving element (e.g., the receiving element 3 of FIGS. 1 and 2) or a gas cylinder portion (e.g., the gas cylinder portion 9 of FIGS. 1 and 2). In yet other examples, the fore sight 1 and/or 201 may be replaced with different types of sight portions (e.g., an aperture sight portion).

Furthermore, in yet other examples, any suitable biasing elements, pins, clamps, or spring elements may be used to retain the coupling elements 7 or 207 coupled to the sight apparatus 100 or 200. Such biasing elements, pins, clamps, or springs may be disposed, for example, adjacent the hinge plates 5, 5′, 205 and/or 205′, the hinge link 6 and/or 206, etc. In other examples, pins may be used to engage respective or corresponding apertures of a stem or body of the coupling elements 7 or 207 to couple the coupling elements 7 or 207 to the sight apparatus 100 or 200.

In yet other examples, the coupling elements 7, 207 may be implemented with, for example, a spring-loaded lever that locks or retains the coupling elements 7, 207 coupled to the sight apparatus 100 or 200. For example, the lever may engage a detent or lip disposed within the passageway 21 or 221 to couple the coupling elements 7 or 207 to the sight apparatus 100 or 200. To remove the coupling elements 7 or 207, the lever is displaced to compress a biasing element so that the lever releases the detent or the lip disposed within the passageway.

Although certain example methods and apparatus have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents. 

1. A sight apparatus for use with firearms, comprising: a first swivel element removably coupled to a second swivel element, wherein the first swivel element includes a first aperture coaxially aligned with a second aperture of the second swivel element to define a passageway; a coupling element removably disposed within the passageway to pivotally couple the first swivel element relative to the second swivel element, and wherein the coupling element includes a retainer portion to engage at least one of the first or second swivel elements to prevent movement of the coupling element along a transverse axis of the passageway when the coupling element is disposed within the passageway.
 2. A sight apparatus as described in claim 1, wherein the coupling element comprises a hinge pin having a cylindrically-shaped body and a head portion, wherein the body includes an annular groove.
 3. A sight apparatus as described in claim 2, wherein the retainer comprises a spring clamp at least partially disposed within the annular groove of the coupling element, wherein the spring clamp is to engage a portion of the first or second swivel portions when the coupling element is coupled to the sight apparatus via the passageway.
 4. A sight apparatus as described in claim 3, wherein the first swivel element comprises a fore sight having a first hinge plate opposite a second hinge plate.
 5. A sight apparatus as described in claim 4, wherein the second swivel element comprises a base having a hinge link, wherein the hinge link is disposed between first and second plates when the fore sight is coupled to the base.
 6. A sight apparatus as described in claim 4, further comprising a bushing coupled adjacent the second hinge plate and having a bore to be coaxially aligned with the passageway, wherein the bore is larger than the second opening of the second hinge plate to define a shoulder.
 7. A sight apparatus as described in claim 6, wherein the spring clamp is disposed adjacent the shoulder to retain or lock the coupling element along the transverse axis of the passageway when the coupling element is disposed within the passageway.
 8. A sight apparatus as described in claim 6, wherein the shoulder or the spring clamp includes a beveled edge so that the spring clamp is compressed within the annular groove of the coupling element when the coupling element is removed from the passageway to disassembly or decouple the first swivel element from the second swivel element.
 9. A sight apparatus as described in claim 1, wherein the coupling element comprises a hinge pin having a stem and a head portion, and wherein the retainer is integrally formed with the coupling element, wherein the retainer comprises a first keyed portion to define a first cross-sectional shape of the coupling element, and wherein the retainer comprises a protruding lip member eccentric from the first keyed portion to define a second cross-sectional shape of the coupling element different than the first cross-sectional shape.
 10. A sight apparatus as described in claim 9, wherein the first aperture of the first swivel element includes a second keyed portion that is shaped to receive the second cross-sectional shape of the coupling element, and wherein the second aperture of the second swivel element includes a third keyed portion that is shaped to receive the first cross-sectional shape of the coupling element.
 11. A sight apparatus as described in claim 10, wherein the second and third keyed portions align to enable the coupling element to be disposed within, or removed from, the passageway, and wherein the second keyed portion of the first swivel element prevents the protruding lip from axially moving within the passageway when the coupling element is coupled to the sight apparatus.
 12. A sight apparatus as described in claim 1, wherein the first swivel portion pivots relative to the second swivel portion between an operating position and a stored position.
 13. A sight apparatus as described in claim 12, further comprising a locking mechanism to lock the first swivel element relative to the second swivel element when the sight apparatus is at the operating position or the stored position.
 14. A sight apparatus described in claim 13, wherein the locking mechanism comprises a lever biased to engage a detent in the second swivel element, wherein the lever is moved against the biasing force of the biasing element via a lever to disengage the detent to pivot the first swivel element relative to the second swivel element.
 15. A sight apparatus as described in claim 1, wherein the base further comprises a retainer plate having a gas housing to be operatively coupled to a muzzle end of a barrel of the firearm.
 16. A sight apparatus as described in claim 1, wherein the coupling element is removed from, or coupled to, the sight apparatus to remove or replace the first or second swivel elements during operational conditions of the firearm.
 17. A sight apparatus for use with a firearm, comprising: a fore sight having a fork-shaped end to define a first hinge plate and a second hinge plate, wherein the first hinge plate has a first aperture coaxially aligned with a second aperture of the second hinge plate, a base having a hinge link, wherein the hinge link has a third aperture that is to coaxially align with the first aperture of the first hinge plate and the second aperture of the second hinge plate to define a passageway when the base is coupled to the fore sight; a hinge pin removably coupled to the passageway, wherein the hinge pin pivotally couples the fore sight relative to the base to enable the fore sight to pivot between a first position and a second position relative to the base, and wherein the hinge pin includes a body portion and a head portion; and wherein the body portion of the hinge pin includes a retainer to engage at least a portion of the hinge link, the first hinge plate, or the second hinge plate to prevent axial movement of the hinge pin within the passageway when coupled to the sight apparatus and the fore sight pivots between the first position and the second position.
 18. A sight apparatus as described in claim 17, wherein the retainer comprises a spring clamp at least partially disposed within an annular groove of a stem portion of the hinge pin, wherein the spring clamp is to engage a shoulder of the second hinge plate to retain the hinge pin within the passageway when the hinge pin is coupled within the passageway.
 19. A sight apparatus as described in claim 17, wherein the retainer comprises a protruding lip adjacent the head portion and a planar portion to define a first cross-sectional portion of the hinge pin, and wherein the planar portion defines a second cross-sectional shape of the hinge pin.
 20. A sight apparatus as described in claim 19, wherein the first aperture is shaped to receive the first cross-sectional shape of the hinge pin and the second aperture is shaped to receive the second cross-sectional shape of the hinge pin, so that the hinge pin may be coupled to, or removed from, the passageway when the first and second apertures aligns, and wherein the hinge pin is retained within the passageway when the first aperture of the fore sight rotates relative to the second aperture of the base between the operating and stored positions.
 21. A sight apparatus for use with firearms, comprising a first swivel element removably coupled to a second swivel element, wherein the first swivel element includes a first aperture coaxially aligned with a second aperture of the second swivel element to define a passageway, and wherein the first aperture includes a first keyed pathway and second aperture includes a second keyed pathway different than the first keyed pathway; a coupling element removably disposed within the passageway to pivotally couple the first swivel element relative to the second swivel element, wherein the coupling element includes a retainer portion to engage at least one of the first or second swivel elements to prevent movement of the coupling element along a transverse axis of the passageway when the coupling element is disposed within the passageway, wherein the retainer has a first cross-sectional portion corresponding to the first keyed pathway and the a second cross-sectional portion corresponding to the second keyed pathway, and wherein the coupling element may be coupled to, or removed from, the passageway when the first and second keyed pathways align to enable passage of the first and second cross-sectional portions of the coupling element.
 22. A sight apparatus as described in claim 21, wherein the coupling element comprises a hinge pin having a head portion and a cylindrically-shaped stem portion, and wherein the retainer comprises a protruding lip adjacent the head portion and a planar portion to define the first cross-sectional portion of the hinge pin, and wherein the planar portion defines the second cross-sectional shape of the hinge pin. 